Elevator safety appliance



Apia] 22, 1924. I 1,491,677

' J. H. CRUTCHFIELD ELEVATOR SAFETY APPLIANCE Filed April 7, 1922 Patented A r. 22, 1924.

UNITED" STATES JOHN H. CRUTGHFIELD, or PARTA, iriLmoI's. I

ELEVATOR SAFETY .errmauonl Application filed April 7,

T 0 all whom it may co'ncern:

Be it known that JOHN H. ,CRUrcHrInLn, a citizen of the United States of America, residing at Sparta, in the county of Bandolph and State of'Illinois, has invented new and useful Improvements in Elevator Safety Appliances, of which the following is a specification.

The object of the invention is to provide a simple and efiicient means for catching and holding an elevator cage in the event ofthe breakage of the hoisting cable or the disarrangement. of the operating means so" as to leave the cage in an otherwise unsupported condition; and with this object in view the invention consists in a construc tion and combination of parts of which a preferred embodiment is shown in the accompanying drawings, wherein Figure 1 is an elevation of an elevator cage and shaft equipped with a safety appliance constructed in accordance with the invention.

Figure 2 is a transverse sectional view of the same taken on the plane indicated by the line 22 of Figure 1.

Figure 3 is a detail view in plan of the attaching links by which connection is made between the hoisting cable and the cage.

The cage which is indicated only in outline at 10 and obviously may be of any pre ferred construction adapted either for passenger use or for hoisting minerals such as coal, ore and the like as for example from mines or similar sources of supply and frequently employed particularly in mine shafts as aconvenient means of hoisting the work men to the surface, and parallel with the guiding tracks 11 of the shaft or frame in which the elevator cage is mounted to slide are arranged racks 12 for traverse by gears 13 revolubly mounted as at 14 upon the car in a common transverse plane and also in the common plane of the racks, and designed to rotate in opposite directions as the car is elevated and lowered.

The adjacent portions of the peripheries of the gears approach to within a comparatively short distance of each other and ar ranged above the same for movement in a plane common therewith is a wedge shaped locking block 15 having toothed downwardly convergent faces 16 which are adapted when the block is lowered to interlock with the teeth of the gears and thereby hold the latter against rotation in a direction to permit 1922.. Serial myssoa ie-jf locking block is adapted to find a position in interlocking engagement with the gears by gravity when suspended in the construction illustrated when inaposition above the plane of approach of the peripheries of the gears', but as'an auxiliary means of actuatin the locking block and as a meansof holding the same against" vibration in the operat on of the oagefand furthermore fas ameans' of insuring the operative engagement of the'block with the-gears should the direction of movement necessary to interlock the same he other than downward, as might occur in certain conceivable arrangements of elevator mechanisms, there is employed a block, actuating spring 16 connected to the apex or reduced end of the block and to a suitable portion of, the car frame such as the bar 17 the tension of the spring being continuously directed to a movement of the block into its engaging relation with the gears. r v

In the construction illustrated the car is supported for elevation and lowering movements b p a hoisting cable 18 connected with the car by means of thesupporting links 19 with which the cablehas a lost motion connection through an elongated guide link 20, and connecting the locking block with this hoisting element is a retainer 21 consisting as shown of a light chain or its, equivalent which is sufiicient when the'hoisting cable is under tension due to the weight of the car to hold the locking block in the inoperative position indicated in Figure 1 in opposition to gravity. and the seating spring 16 or other yielding means tending to advance theblock into operative engagement with the gears.

Under ordinary working conditions the locking block, therefore, is held out of engagement with the gears and the operation of the elevator corresponds with those now in common use in mine shafts and the like, but in the event that the hoisting cable should break or the drum actuating clutch or brake of the engine should fail to operate or respond to the control of the operator and thereby permit the cable to pay out at an excessively rapid rate, the locking block will. immediately be moved into interlocking engagement with the gears and obviously when in engagement the. action of the gears thereon will tend to force the block downwardly into a position between the gears and thus force the gears outward to exert a downward movement of the cagefl This era spreading action upon the racks and thus bind the car and lock it in a fixed position.

Moreover it will be obvious that the action of the block will occur immediately upon the release or reduction of strain on the cable and that immediately thebraking action incident to its engagement'with "the' gears will occur so that not more than a. fewinches of drop of the car can occur in the event I ofan'accident before the locking g thereof ensues,and henceubefore any con- -siderable momentum. can be acquired by the car.

7 Having described the invention, what is 'claimedas new and useful is -A safety appliance, forelevators comprisv hi ing vertically disposed racks arrangedparalr lel with each other, anelevator car mounted the teeth of the respective racks,- said" gear :for movement between ther'acks, gear twheels journaled; upon the canand meshing. with :WlflGGlSj' lyingdn; ,the same" Plane and being spaced from each other at their-inner sides,

a locking block lying in the plane of the gear wheels and provided at :its side edges the links the parts being so arranged that when the :car'is being liftedby the pull of the cable, theiinneriendsof theilinks are 1 elevated and the locking block is held spaced fromthe peripheries of the gear'wheels; and

a when the: cable-becomes: slack,. the; locking block; is drawn:- into engagementwith i the perforations of the gear wheelsbythe. action 'of ithe spring which; iseconnected ,withthe block". and athecar.

7 In testimony whereof he ,aflixes his 3 signature.

g [JOHN H; .CRUTCHFI-ELD. 

